Drum type heat exchanger



Feb. 7, 1961 R. w. Kran-2ER 2,970,312

DRUM TYPE HEAT ExcHANGx-:R

Filed June 14, 1956 2 Sheets-Sheet 1 Z2 Feb. 7, 1961 R. w. KRITZER DRUMTYPE HEAT EXCHANGER 2 Sheets-Sheet 2 Filed June 14, 1956 iinited StatesPatent() DRUM TYPE HEAT EXCHANGER Richard W. Kritzer, Chicago, Ill.Peerless of America, 5830 N. Pulaski Road) Filed June 14, 1956, Ser. No.591,491

1 Claim. (Cl. 257-241) The invention relates to a heat-exchanger of thedrumtype which includes spirally coiled tubing and fins, and thefabrication thereof.

One object of the invention is to provide a heat-exchanger of this typewhich can be expeditiously and economically fabricated.

Another object of the invention is to provide an improved method offabricating heat-exchangers of this type.

Other objects will appear from the detail description.

The invention consists in the many novel features hereinafter set forthand more particularly by the claim at the conclusion hereof.

In the drawings:

Fig. 1 is a plan view of an exchanger embodying the invention, the drurnor casing being shown in section;

Fig. 2 is a section taken on line 2 2 of Fig. l;

Fig. 3 is a perspective view of a portion of the finforming structure orstrip;

Fig. 4 is a section on line 4-4 of Fig. 1; and

Fig. 5 is a section taken on line 5 5 of Fig. 1.

The invention is exemplified in a heat-exchange unit which comprises: adrum or casing whichincludes a sleeve or hub and an annular jacket ordrum 11;- a series of three coils of tubing 12, 13 and 14, ofcylindrical cross section, each including spiral convolutions inside-by-side relation and spaced apart radially. A header 16 iscommunicatively connected to the inner end of the coils adjacent sleeve10 and a header 17 is communicatively connected to the outer ends of thecoils for the circulation of a fluid, usually a refrigerant, through thecoils, one of the headers serving as an inlet and the other as an outletfor the fluid. The radial spacings olf the convolutions of the coilsform a spiral passage between the convolutions of the coils for the flowof air longitudinally through the drum or casing. An air impeller (notillustrated) is usually mounted over the coils and driven by an electricmotor which may be mounted in the sleeve 1li for forcing air to becooled through the drum, as well understood in the art.

An elongated or continuous strip of fin-stock, such as thin sheetaluminium, is fabricated into a fin-structure, generally designated 1S,which fits and is confined in the spiral space between the convolutionsof the series of coils. This iin-structure is utilized to transfer heatfrom the fluid in the coils to the air which contacts said structure andthe tubing. The fin-structure includes a series of substantiallycoplanar lin-sections 20 which are adapted to extend across or span thespiral space between the convolutions of the entire series of coils andintegral ends 21 which are formed by bends which alternately connectopposite ends of contiguous sections 20 and function as seats for thecoils of tubing. Each end 21 includes substantially flat portions 22 andcurved portions 23 which conform to the cross-sectional contour of thetubing for closely fitting contact between the outer faces of ends 21and the convolutions of the coils. Each tin-section 20 has an end 21provided with seats for the outer pethe sleeve.

ripheral portions of one convolution of each of the spiral coils 12, 13and 14, and an opposite end 21 provided with seats for the innerportions of the next convolutions of the coils, the strip forming thefin-structure being of sufficient width for that purpose. The structure2li before assembly with the coils is readily flexible into generallyspiral contour to conform to the spiral convolutions of the c-oils, and,after said assembly, provides fins in the air stream between saidconvolutions. The tubing of the coils is bendable spirally around thefin-structure to produce pressure-contact between the seats on the ends21 of the fin-structure and Athe contacting portions of the coils. Thefaces of sections 20 and inner faces of ends 21 are exposed to the airstream through the drum. In shaping the strip of fin-stock into thecontinuous structure 15, and bending the metal in the ends 21 to formthe seats for the tubing, the metal is ruptured as at 24, at the crestsof the curved portions 23. This provides for ilexibility in said curvedportions to conform to the crosssectional contour of the contiguoustubing, and also provides openings for the flow o-f air to the clearancebetween the coils which are in side-by-side relation.

A portion of the inner convolution of each of the coils 12, 13 and 14extends around a portion of the sleeve 10 and thence spirally around tothe adjoining end of the next convolution where the inner end of thefin-structure is located. A first elogated tapered batlle 30 closes thegap between sleeve 10 and the header 16 where said portion of the innerconvolutions extend spirally away from This baille extends to thefin-section 20 on the inner end of the spirally coiled fin-structureadjacent header 16. A portion of the outer convolution of each of saidcoils extends spirally around casing 11. A second elongated tubularbaille 31 closes the gap around said portion and the casing 11 andextends circumferentially to the header 17 and the fin-section 20 on theouter end of the fin-structure. These baffles and construction confinethe longitudinal air flow through casing to the spirally extendingradial spaces between the convolutions of the coils in which thetin-structure is disposed, for contact ing the air with thefin-structure and efficiency in heat transfer.

In the fabrication of the unit, the fin-structure 15 is of sufficientlength to extend between the spiral gaps between the convolutions of thecoils between the headers 16 and 17. Before assembly, the fin-structurewith the coils or casing is linear and readily bendable into spiralcontour because the sections 20 are readily flexible between -the ends21. This facilitates the flexing of the strip 15 into spiral contourconformably to the coils of tubing. In assembling the unit, the header16 is fxedly held in the baille 30 which is secured to the sleeve or hub1t). The tubing for the coils 12, 13 and 14 which is sufficientlybendable transversely for this purpose, is bent around the sleeve 10 andbaille 30 to progressively form the inner convolution of each of thecoils. The fin-structure 15 is folded around the outer periphery of saidinner convolutions. This bending of the tubing and folding of thefinstructure is progressively continued until the coils andfin-structure are entirely assembled in spirally wrapped relation.

The assembled fin-structure and coils 12, 13 and 14 are pressed togetherand contracted and while so contracted are inserted sidewise into thedrum 11. This contraction secures the ends 21 of the fin-structure inthe coils. The concave seats on the ends 21 of the finstructure areinterlocked against relative movement coaxially of the sleeve 10 anddrum 11, with the header 16 adjacent baille 30 and header 17 adjacentbaille 31. The inner ends of the coils are confined by a flange 4t) onone end of sleeve 10 and a ring 41, and the other ends of the coils areconfined and held in the drum between a flange ft2-on the drum and aring 43. The assembled coils and iin-structure are then secured togetherwith pressure contact or in close-fitting relation for eficientheat-transfer from the fluid in the coils to the nstructure. The airpassing through the spirall gaps between the convolutions o the coilswill Contact the faces of the tins formed by sections 20, the innerfaces of bends 21 and the exposed inner face portions of the coilsbetween sections.

The invention exemplifies a heat-transfer element of the drum-type whichis eicient in operation and simple in construction and an economicalmethod of fabricating and assembling the unit.

The invention is not to be understood as limited to the details setforth, since these may be modied Within the scope of the appended claimwithout departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

A drum type heat exchange unit comprising in combination a drum casingincluding an open-ended tubular centrally disposed hub and an outercylindrical casing shell concentric with the hub and spaced radiallytherefrom, a rst tubular header disposed within said outer cylindricalcasing shell and in close proximity to said tubular hub exteriorly ofthe, latter, a second tubular header disposed within said outercylindrical casing shell and in close proximity to the latter, the axesof said tubular headers extending parallel to the common axis of thetubular hub` andV cylindrical casing shell, a plurality of verticallyspaced, superimposed, uniformly involute tubular coils of cylindricalcross section disposed within said drum casing between the hub andcasing shell, the inner ends of said involute tubular coilscommunicating with the interior of said lirst tubular header and theouter ends of said involute tubular coils, corn-i municating with theinterior of said second tubular header, the innermost convolutions ofsaid involute coils being partially wrapped around said hub incontiguous relation to a major arcuate portion of the cylindricalsurface thereof, the outermost convolutions of said involute coilsclosely hugging a major arcuate portionof 4 the, inner cylindricalsurfaceV of the casing shell, a tirst elongated tapered baille memberlling the space existing between the innermost convolutions of saidinvolute coils and the outer cylindrical surface of the tubular hub andpartially encompassing said rst tubular header and the hub, a secondelongated tubular baflle member filling the space existing between theoutermost convolutions of said involute coils and the inner cylindricalsurface of said casing shell, and a continuous strip of lin stockdisposed between adjacent convolutions of the various involute l'coilsand extending in involute fashion from said sec- .ond bale member tosaid rst baille member, said fin stock providing a multiplicity ofclosely spaced radially extending lin sections common to and bridgingthe distance between the adjacent convolutions of each involute coil,the adjacent inside edges of alternate pairs of adjacent n sectionsbeing connected together by integral webs of full fm stock height, theadjacent outside edges of other alternate pairs of adjacent lin sectionsbeing connected together by integral webs of full lin stock height, eachof said webs spanning said superimposed involute coils and being formedwith imperforate curved seats in intimate facefto-face contact with thevarious coil convolutions, the material of each web between adjacentcurved seats being ruptured to dene openings through the web, andpresenting curved lingers which closely hub the curved wall of theadjacent coil convolutions, thereby lending flexibility -to said curvedseats as well as aording intimate heat exchange between the curved seatsand theA coil convolutions.

References Cited in the le of this patent UNITEDv STATES PATENTS1,822,068l Summers` et al Sept. 8, 1931 1,849,396 Baetz Mar. 15, 19322,035,665 Palmer Mar. 3,1, 1936 2,164,854 Booth et al. July 4, 19392,213,463 Fink Sept. 3, 1940 2,657,018 Simpelaar Oct. 27, 1953 2,716,802Greer Scpt. 6, 1955 2,820,617 Tadewald Jan. 21, 1958

